Datasheet

Instructions M95256-W M95256-R M95256-DR M95256-DF
24/52 DocID12276 Rev 20
Figure 13. Byte Write (WRITE) sequence
1. Depending on the memory size, as shown in Table 5, the most significant address bits are Don’t Care.
In the case of Figure 13, Chip Select (S) is driven high after the eighth bit of the data byte
has been latched in, indicating that the instruction is being used to write a single byte.
However, if Chip Select (
S) continues to be driven low, as shown in Figure 14, the next byte
of input data is shifted in, so that more than a single byte, starting from the given address
towards the end of the same page, can be written in a single internal Write cycle.
Each time a new data byte is shifted in, the least significant bits of the internal address
counter are incremented. If more bytes are sent than will fit up to the end of the page, a
condition known as “roll-over” occurs. In case of roll-over, the bytes exceeding the page size
are overwritten from location 0 of the same page.
The instruction is not accepted, and is not executed, under the following conditions:
• if the Write Enable Latch (WEL) bit has not been set to 1 (by executing a Write Enable
instruction just before),
• if a Write cycle is already in progress,
• if the device has not been deselected, by driving high Chip Select (S
), at a byte
boundary (after the eighth bit, b0, of the last data byte that has been latched in),
• if the addressed page is in the region protected by the Block Protect (BP1 and BP0)
bits.
Note: The self-timed write cycle t
W
is internally executed as a sequence of two consecutive
events: [Erase addressed byte(s)], followed by [Program addressed byte(s)]. An erased bit
is read as “0” and a programmed bit is read as “1”.
C
D
AI01795D
S
Q
15
21 345678910 2021222324252627
1413 3210
28 29 30
High Impedance
Instruction 16-Bit Address
0
765432 0
1
Data Byte
31